A known proton therapy system with a plurality of treatment stations is described in U.S. Pat. No. 4,870,287. Such multi-station systems comprise a proton accelerator, typically an isochronous cyclotron or a synchrotron for providing a proton beam. Furthermore, the known multi-station systems comprise a beam guiding system for guiding the proton beam from the proton accelerator to the various treatment stations. In addition, the known devices include so-called gantries, which allow the proton beam to impinge from different directions on the irradiation object placed isocentrically at the irradiation station. Such gantry is a pivotally mounted device, in which the proton beam arriving along the swivel axis is coupled in, and in which the proton beam is deflected away and onwards from the swivel axis by a corresponding radiation optics, such that by rotating the gantry it impinges on the irradiation station, which mostly is located on the swivel axis of the gantry, from different directions.
In the known multi-station systems, only one particle accelerator is required for a plurality of treatment stations, so that the comparatively high expenditure for great accelerator facilities is distributed over a plurality of treatment stations. On the other hand, the multitude of treatment stations increases the total costs for the facility. In addition, comparatively large areas and buildings are required for the multi-station systems, which involves high costs in particular because of the radiation protection requirements. In multi-station systems, the treatment plans of the individual treatment stations must also be adjusted to each other, as it is not possible to simultaneously irradiate at different treatment stations. This leads to the further disadvantage that a delay at one treatment station involves a delay at the other treatment stations.
Therefore, it is the object of the present invention to propose an improved irradiation device. In particular, the irradiation device of the invention should have a compact configuration and require less space, so that the investment costs can be lowered as compared to known facilities. In addition, this invention should allow to omit the matching of treatment plans at various treatment stations.
In accordance with the invention, this object is solved by an irradiation device with the features of claim 1. Preferred aspects can be taken from the sub-claims.
The irradiation device of the invention comprises a particle accelerator for providing a beam of heavy charged particles (particle beam). In accordance with the invention, the particle accelerator is mounted on a carrier pivotable about at least one axis. The carrier is part of a swivelling device, which is configured such that the particle beam directed onto the treatment station can be swivelled by rotating the carrier. For mounting on the carrier, in particular compact accelerators can be used. With the configuration of the irradiation device in accordance with the invention, a particularly compact single-station irradiation system can be realized. Mounting on the pivotable carrier allows a simplification of the beam guidance, as in particular coupling a stationary beam into the swivelling device can be omitted.
The swivelling device can be configured in particular in the manner of the known gantries. The pivotable carrier then advantageously constitutes a pivotable gantry frame. The accelerator then is mounted on this gantry frame and is swivelled with the same, so that coupling an externally generated beam fixed in space into the movable gantry structure can be omitted.
In a preferred aspect, the pivotable carrier has a bent structure with at least two legs, wherein the swivel axis extends through at least two legs. With such a structure, a particularly stable swivelling device can be realized.
Furthermore, the pivotable carrier preferably has a U-shaped structure, i.e. two substantially parallel side legs with a connecting piece. Advantageously, the swivel axis extends substantially vertically through the two legs of the U-structure. Furthermore advantageously, the accelerator is mounted in the terminal portion of a leg of the U-structure. The aforementioned preferred aspects provide for a particularly favorable weight distribution, so that the swivelling device can be rotated more easily.
Another advantageous aspect consists in that one leg of the U-structure is formed with an opening and/or recess in the vicinity of the swivel axis, so that a clearance is left in this leg in the vicinity of the swivel axis for placement of the irradiation object. This configuration provides for arranging the irradiation station in the region of this leg in the vicinity of the swivel axis, so that an irradiation object positioned there can be irradiated isocentrically.
Advantageously, means for guiding and/or shaping the particle beam are mounted on the carrier. With these means, the particle beam can be guided from the accelerator to the point of emission and can be shaped, for instance focussed or expanded, in the process.
In another preferred aspect, a means for modifying or reducing the particle energy, for instance an energy degrader, is mounted on the carrier. This means can be used for varying the energy of the particles impinging on the irradiation object.
In another preferred aspect, a radiation head or nozzle with components for the controlled emission of a particle beam in the direction of the irradiation station is mounted on the carrier. Advantageously, these components comprise one or more means which are configured such that an irradiation by the pencil-beam scanning method is possible. In the pencil-beam scanning method, a volume to be irradiated in the irradiation object is raster-scanned in three dimensions. For this purpose, the particle beam is focussed on a beam cross-section which lies distinctly below the size of typical irradiation volumes. Due to the Bragg peak, the major part of the radiation dose is deposited in a depth depending on the particle energy. By using a suitably focussed pencil beam, many small volumes, so-called voxels, thus can be irradiated, so that irradiation volumes of any shape—for instance tumors—can be raster-scanned with the pencil beam in three dimensions. The shift in beam direction, i.e. depth raster scanning in the irradiation object, is achieved by varying the particle energy, mostly by using an energy degrader. The shift in the two directions vertical to the beam, i.e. raster scanning in the plane vertical to the beam, is achieved by deflection means, in particular deflection magnets. For raster scanning by the pencil-beam scanning method, the components of the nozzle therefore advantageously comprise one or more means for deflecting vertical to the particle beam and/or a means for varying the particle energy and/or a means for monitoring the beam position and/or a means for monitoring the radiation dose. With such means, a particle beam shaped like a pencil beam can be used particularly advantageously for raster scanning an irradiation object.
In another preferred aspect, a cyclotron, in particular a superconducting synchrocyclotron, is used as particle accelerator. Advantageously, a cyclotron with a strong magnetic field is chosen, which can be realized in particular with a superconducting synchrocyclotron. Due to the strong magnetic field, the cyclotron can have a particularly compact configuration. It facilitates mounting on the swivelling device and its movement. In another preferred aspect, the device at the irradiation station includes a movable patient couch for positioning irradiation patients. Particularly advantageously, the patient couch can be moved translatorily in the horizontal plane and/or be rotated. This provides for positioning an irradiation patient such that a tumor to be irradiated is located inside the irradiation region covered by the irradiation device, and the tumor can be irradiated from different directions.
In accordance with another preferred aspect, the particle accelerator provides a beam of protons and/or heavier ions, in particular He2+ or C6+, as a beam of heavy charged particles. With the different irradiation particles, different treatment results can be achieved.